$('.sidebar-list').mouseover(function(){
    // console.log( $(this))
    console.log('移入')
  
    $('.sidebar-list-item').css('display','block')

})
$('.sidebar-list').mouseout(function(){
    // console.log( $(this))
    console.log('移入')
 
    $('.sidebar-list-item').removeAttr('style','')
})
console.log($('.sidebar-list'))